/* Copyright (c) 2010, Carl Burch. License information is located in the
 * com.cburch.logisim.Main source code and at www.cburch.com/logisim/. */

package com.cburch.draw.tools;

import java.awt.Color;
import java.awt.Cursor;
import java.awt.Graphics;
import java.awt.event.InputEvent;
import java.awt.event.KeyEvent;
import java.awt.event.MouseEvent;
import java.util.Arrays;
import java.util.List;

import javax.swing.Icon;

import org.apache.commons.collections15.list.UnmodifiableList;

import com.cburch.draw.actions.ModelAddAction;
import com.cburch.draw.canvas.Canvas;
import com.cburch.draw.model.CanvasModel;
import com.cburch.draw.model.CanvasObject;
import com.cburch.draw.shapes.DrawAttr;
import com.cburch.draw.shapes.LineUtil;
import com.cburch.draw.shapes.Poly;
import com.cburch.logisim.data.Attribute;
import com.cburch.logisim.data.Location;
import com.cburch.logisim.util.Icons;

public class LineTool extends AbstractTool {
    private DrawingAttributeSet attrs;
    private boolean active;
    private Location mouseStart;
    private Location mouseEnd;
    private int lastMouseX;
    private int lastMouseY;

    public LineTool(DrawingAttributeSet attrs) {
        this.attrs = attrs;
        active = false;
    }

    @Override
    public Icon getIcon() {
        return Icons.getIcon("drawline.svg");
    }

    @Override
    public Cursor getCursor(Canvas canvas) {
        return Cursor.getPredefinedCursor(Cursor.CROSSHAIR_CURSOR);
    }

    @Override
    public List<Attribute<?>> getAttributes() {
        return DrawAttr.ATTRS_STROKE;
    }

    @Override
    public void toolDeselected(Canvas canvas) {
        active = false;
        repaintArea(canvas);
    }

    @Override
    public void mousePressed(Canvas canvas, MouseEvent e) {
        int x = e.getX();
        int y = e.getY();
        int mods = e.getModifiersEx();
        if ((mods & InputEvent.CTRL_DOWN_MASK) != 0) {
            x = canvas.snapX(x);
            y = canvas.snapY(y);
        }
        Location loc = Location.create(x, y);
        mouseStart = loc;
        mouseEnd = loc;
        lastMouseX = loc.getX();
        lastMouseY = loc.getY();
        active = canvas.getModel() != null;
        repaintArea(canvas);
    }

    @Override
    public void mouseDragged(Canvas canvas, MouseEvent e) {
        updateMouse(canvas, e.getX(), e.getY(), e.getModifiersEx());
    }

    @Override
    public void mouseReleased(Canvas canvas, MouseEvent e) {
        if (active) {
            updateMouse(canvas, e.getX(), e.getY(), e.getModifiersEx());
            Location start = mouseStart;
            Location end = mouseEnd;
            CanvasObject add = null;
            if (!start.equals(end)) {
                active = false;
                CanvasModel model = canvas.getModel();
                Location[] ends = { start, end };
                List<Location> locs = UnmodifiableList.decorate(Arrays.asList(ends));
                add = attrs.applyTo(new Poly(false, locs));
                add.setValue(DrawAttr.PAINT_TYPE, DrawAttr.PAINT_STROKE);
                canvas.doAction(new ModelAddAction(model, add));
                repaintArea(canvas);
            }
            canvas.toolGestureComplete(this, add);
        }
    }

    @Override
    public void keyPressed(Canvas canvas, KeyEvent e) {
        int code = e.getKeyCode();
        if (active && (code == KeyEvent.VK_SHIFT || code == KeyEvent.VK_CONTROL)) {
            updateMouse(canvas, lastMouseX, lastMouseY, e.getModifiersEx());
        }
    }

    @Override
    public void keyReleased(Canvas canvas, KeyEvent e) {
        keyPressed(canvas, e);
    }

    private void updateMouse(Canvas canvas, int mx, int my, int mods) {
        if (active) {
            boolean shift = (mods & InputEvent.SHIFT_DOWN_MASK) != 0;
            Location newEnd;
            if (shift) {
                newEnd = LineUtil.snapTo8Cardinals(mouseStart, mx, my);
            } else {
                newEnd = Location.create(mx, my);
            }

            if ((mods & InputEvent.CTRL_DOWN_MASK) != 0) {
                int x = newEnd.getX();
                int y = newEnd.getY();
                x = canvas.snapX(x);
                y = canvas.snapY(y);
                newEnd = Location.create(x, y);
            }

            if (!newEnd.equals(mouseEnd)) {
                mouseEnd = newEnd;
                repaintArea(canvas);
            }
        }
        lastMouseX = mx;
        lastMouseY = my;
    }

    private void repaintArea(Canvas canvas) {
        canvas.repaint();
    }

    @Override
    public void draw(Canvas canvas, Graphics g) {
        if (active) {
            Location start = mouseStart;
            Location end = mouseEnd;
            g.setColor(Color.GRAY);
            g.drawLine(start.getX(), start.getY(), end.getX(), end.getY());
        }
    }

    static Location snapTo4Cardinals(Location from, int mx, int my) {
        int px = from.getX();
        int py = from.getY();
        if (mx != px && my != py) {
            if (Math.abs(my - py) < Math.abs(mx - px)) {
                return Location.create(mx, py);
            } else {
                return Location.create(px, my);
            }
        }
        // should never happen
        return Location.create(mx, my);
    }
}
